Elissa Newport - US grants

This research will investigate the structure and acquisition of American Sign Language (ASL), a natural language of the deaf of North America. ASL may be acquired as a primary language either early or late in life, and either from native signers or from signers who themselves acquired the language late in life. Its study therefore provides an unusual opportunity to investigate the consequences of early vs. late experience, and of wide variations in input environment, on the process by which a language is acquired and the ultimate character of its users' knowledge. Eight experiments are proposed, to test adult users of ASL as well as children who are in the process of acquiring ASL, with a test battery of ASL phonology, morphology, and syntax which we will devise. Given our previous results, these experiments are expected to demonstrate: 1) that there are striking differences in the knowledge of a language that users attain as a function of when they began to learn that language, and 2) that there is striking uniformity in the knowledge of a language that users attain when they begin learning the language in infancy, despite wide variations in input environments. In addition, the experiments should reveal whether these phenomena are due to the nature of the acquisition process, to hitherto unnoticed details of the input, or to interference (or the lack of interference) from English. The results should contribute to our understanding of the importance of early experience for language acquisition, and to the character of learning in childhood vs. adulthood. In addition, they should contribute to decisions regarding language exposure, whether spoken or signed, in deaf education and parent counseling.

This research will investigate the structure and acquisition of American Sign Language (ASL), a natural language of the deaf of North America. ASL may be acquired as a primary or second language, either early or late in life, and either from native signers or from signers who themselves acquired the language late in life. Its study therefore provides an unusual opportunity to investigate the consequences of early vs. late experience, and of wide variations in input environment, on the process by which a language is acquired and the ultimate character of its users' knowledge. Six studies are proposed, four investigating the consequences of early vs. late exposure and two investigating the consequences of impoverished input environments on language acquisition. The studies of early vs. late exposure are intended to follow up on previous findings that age of exposure strongly influences performance, many years later, in both a first and second language. These new studies will investigate whether the effects of age of exposure differ in degree for first vs. second language acquisition, whether they extend to the application of universal syntactic principles in the language, and how they manifest themselves in the initial few years of learning the language. The studies of impoverished of a language are able to reorganize inconsistent aspects of their input and thereby surpass their own input models, acquiring a language rather different than the one to which they were exposed. New studies will investigate the range of linguistic structures for which this is true, and the mechanisms by which such language change occurs. The results should contribute to our understanding of the importance of early experience for language acquisition, and to the character of learning in childhood vs. adulthood. In addition, they should contribute to decisions regarding language exposure, whether spoken or signed, in deaf education and parent counseling.

This proposal requests a new training grant to support a predoctoral and postdoctoral training program in Learning, Development, and Biology, housed within the Department of Brain and Cognitive Sciences at the University of Rochester. The training program includes nine faculty members from the Department of Brain and Cognitive Sciences, all of whom study learning and development of complex behaviors in humans and animals. This program reflects our recognition of the potential for a synthetic approach to the study of learning: current approaches to computational modeling, neurophysiological, and behavioral investigations have begun to share enough formal similarities to be mutually informative; at the same time, they bring distinctive perspectives to the problem of learning and development, so that their integration can lead to new insights. Our program therefore aims to train students in the study of learning and developmental plasticity from the joint perspectives of behavioral, computational, and neurophysiological approaches. Surrounding our group at the University are additional programs in the mature functioning of each of the relevant domains and systems. We request support for 2 predoctoral students and 2 postdoctoral students per year; when combined with other sources of support, this will permit a larger group of approximately 5-7 predoctoral students in this program, as well as predoctoral and postdoctoral students in other related programs. Trainees will enter through the Department of Brain and Cognitive Sciences and will be trained in core courses and advanced seminars in Learning, Development & Biology, Language & Cognition, Perception, and Basic Neuroscience, and in research methods, courses, and research experience in behavioral studies, computational modeling, and neuroscience studies. This breadth of training is made possible by the fact that our program faculty have degrees in 5 different disciplines and ourselves conduct research on overlapping problems from a variety of different methodological approaches. We currently advise 10 predoctoral students with a focus on learning and developmental plasticity, who exemplify the high quality of students we are able to attract.

Both humans and non-human primates show remarkable learning abilities. However, these abilities are often limited to certain domains, developmental periods, or behavioral contexts. For example, nearly all humans acquire one or more complex linguistic systems-that is, languages -- but not all humans acquire complex musical systems. Similarly, non-human primates are exceptionally adept at learning to forage for and categorize different types of food, but are severely limited in acquiring complex communication systems. Also, both humans and non-human primates appear to learn best in several domains during early periods of development. Thus, learning is nearly always characterized by specializations, rather than by general-purpose mechanisms. Understanding the constraints on learning will contribute to basic research, by accounting for domain- and species-specializations, and to applied research, by refining our understanding of which domains, ages, and contexts are optimal for human
learners.

The goal of the present research project is to explore the ability of human adults, children, infants, and non-human primates (Tamarins) to learn rapid sequential events. A prime example of a rapid sequential event is language, in which sounds are combined to form words, and words are combined to form sentences. Recent findings have demonstrated that human adults and infants can rapidly extract and remember very detailed 'statistics' of linguistic input, such as the frequency and probability that one syllable will follow another. In our proposed research, we will employ miniature artificial 'languages' which simulate some of the structural properties of natural languages, but which can be built with equivalent structures across different domains (speech sequences, tone sequences, visual sequences, motor sequences). At issue is the facility humans and non-human primates show for the extraction of statistical structure from these different learning materials. Are they equally sensitive to the distributions of elements and higher order structure in the materials? Do learning abilities differ across learners of different ages and species, and across different structures and domains?

In addition to behavioral experiments with humans and non-human primates, a series of computational studies will allow us to investigate the formal properties of learning mechanisms, in order to ask what architectural and neural differences might underlie such differences in learning abilities. What kinds of computational architectures can learn the types of regularities and patterns that human infants learn? Is the inability of adults or non-human primates to learn some types of complex sequential events due to the absence of a learning device specialized for that domain, or could small differences in computation and/or memory lead to large differences in learning outcome?

With support from a National Science Foundation Major Research Instrumentation award, Dr. Richard Aslin and his colleagues at the University of Rochester will establish the Rochester Center for Brain Imaging (RCBI). The overall goal of this new center is to assess the plasticity of the adult and child brain as it adapts to altered and varied experiences. One type of alteration is the loss of sensory input in a single modality (e.g., the loss of vision or hearing because of blindness or deafness). Previous research at Rochester has shown that congenitally deaf individuals who use sign language do so with the same parts of the brain (the left hemisphere) that are usually used for spoken language, despite relying on the visual rather than the auditory modality. Deaf individuals also have greater sensitivity to patterns of movement in the peripheral visual field because they rely more on signed language inputs delivered in the visual modality. These patterns of brain plasticity are the result of altered sensory input during early development and have important implications for the brain's ability to compensate for deprivation and injury, provided that it has time during early development to adapt to these unusual circumstances. Similar mechanisms of plasticity may be present in adults as they learn a new task or compensate for brain injury. The Rochester group will use functional magnetic resonance imaging (fMRI) to study both long-term (developmental) and short-term aspects of brain plasticity in adults, children, and non-human primates. The research will provide important insights into the neural mechanisms of learning and plasticity and the keys to the brain's ability to adapt to novel experiences.

Working with a team of cognitive scientists and neuroscientists, as well as magnetic resonance physicists and image processing engineers, Dr. Aslin will supervise the purchase, installation, and operation of a 3 tesla (T) fMRI system designed to measure the microscopic changes in blood oxygen level that occur in localized regions of the brain as participants perform a variety of tasks. This system, which is state-of-the-art in the field of human brain imaging, will provide a group of over 30 researchers from the University of Rochester and Cornell University (90 miles from Rochester) with the capability to explore a variety of issues in human brain plasticity and recovery of function after natural deprivation, injury, or disease. A key feature of the new center is a team of physicists and engineers who will develop new ways for fMRI to reveal even more fine-grained details about the functioning and visualization of the brain.

This project is important for several reasons. It will provide a first-class facility for non-invasive brain imaging to a group of researchers at Rochester who have already demonstrated their ability to conduct cutting-edge research in cognitive neuroscience. The RCBI will also play a significant role in the training of future scientists by actively involving graduate and undergraduates students from the University of Rochester and Cornell University, as well as undergaduates from the State University of New York at Geneseo (a non-Ph.D.-granting college located 30 miles from Rochester) in state-of-the-art brain imaging research. The new center provides an excellent vehicle to teach the principles of fMRI to a new generation of students who will become leaders in the field of cognitive neuroscience.

DESCRIPTION (provided by applicant): This proposal requests continuing support for a predoctoral and postdoctoral training program in Learning, Development, and Biology, housed in the Department of Brain and Cognitive Sciences at the University of Rochester. The training program includes eleven faculty members, all of whom study learning and development of complex behaviors in humans and animals. This program reflects our recognition of the potential for a synthetic approach to the study of learning: computational, neurophysiological, and behavioral investigations of learning and developmental plasticity ask many of the same questions and are mutually informative; at the same time, they bring distinctive perspectives to the problems of learning and development, so that their integration leads to new insights. Our program therefore aims to train students in the study of learning and developmental plasticity from the joint perspectives of behavioral, computational, and neurophysiological approaches. Surrounding our group at the University are programs in the mature functioning of each of the relevant domains and systems. We request support for 4 predoctoral and 2 postdoctoral students per year; when combined with other sources of support, this permits approximately 10-12 predoctoral students in this program, as well as other students in related programs. Trainees enter through the Department of Brain and Cognitive Sciences and are trained in core courses and advanced seminars in Learning, Development & Biology, Language & Cognition, Perception, and Basic and Integrative Neuroscience, and in research methods courses and research experience in behavioral studies, computational modeling, and neuroscience studies. This breadth of training is made possible by the fact that our program faculty have degrees in 5 different disciplines and conduct research on overlapping problems from a variety of different methodological approaches. Our current trainees with a focus on learning and developmental plasticity exemplify the high quality of students we are able to attract; our recent graduates exemplify the success we have had in placing our students in academic and research positions.

DESCRIPTION (provided by applicant): Many fundamental issues in the study of human language-the role of early experience, the concept of a "critical period," and the contributions of input versus internal predispositions in language acquisition-are difficult to investigate because most children are, fortunately, exposed to rich, fluent input to their primary language from birth. However, deaf children often acquire signed languages from greatly reduced linguistic input. Our research investigates how well they do this, and how languages that emerge from reduced input develop and change over time. These questions are theoretically significant and also crucial for decisions in the lives of deaf children. We propose to continue 3 lines of work. One line of research studies the development of young sign languages, whose grammars are being built and expanded as they are acquired from reduced input. In one setting we are observing 'home sign' systems of isolated deaf children. In a second setting we are studying a family sign language that has been used and handed down across several generations on a remote fishing island. A second line of research examines the early linguistic structure of American Sign Language and the way the language expanded as it passed through early generations of signers. A third line of research investigates the questions of input and language development in a laboratory paradigm, using a miniature language learning technique with hearing adults and children to investigate how languages are acquired and changed when input is reduced or altered. This research will contribute to our understanding of the relation between input and outcome in language acquisition, and of the mechanisms by which children acquire their native languages. In addition, it will contribute to decisions regarding early language exposure, whether signed or spoken, in deaf education and parent counseling.

DESCRIPTION (provided by applicant): This proposal requests continuing support for a training program in Plasticity, Development, and Cognitive Neuroscience, housed in the Department of Brain and Cognitive Sciences at the University of Rochester. Our program includes eleven faculty members who study neural plasticity in the learning and development of complex behaviors in humans and animals. We are an unusual group in that we span a highly interdisciplinary range: our faculty have degrees in 6 different fields and train our students to approach neural plasticity from the joint perspectives of behavioral science, computational modeling, and neuroscience. We have spent the last 10 years training our students to utilize these interdisciplinary methods to achieve novel insights into the mechanisms by which experience alters the mind and brain, in systems ranging from language acquisition and bird song to visual perception and motor learning. We have attracted outstanding students and have placed them in postdoctoral and faculty positions at top universities. Our work on statistical learning, Bayesian approaches to perception, and the cognitive and neural mechanisms underlying experiential change during learning and development has helped to shape a new understanding of these problems. In the newest phase of our research and graduate training, we are beginning to link our understanding of neural plasticity to the treatment of developmental and neurological disorders. Our faculty and students already use enhanced experiences in the lab to stimulate perceptual learning and have established links for future work with a range of patient populations, including patients with cortical visual impairments and amputees with surgically re-attached hands. The early evidence from this research suggests that an understanding of the principles by which experience normally alters cognition and the brain can be effectively used to provoke recovery of function in the cortex. We are also developing techniques for recording from the brains of awake neurosurgical patients and for using functional magnetic resonance and optical imaging to study the normal course of development in humans and animals as compared with the course of development in disorders such as autism, ADHD, heterotopia (where there is a developmental doubling of cortical layers), and other neurodevelopmental disorders. While our primary research focus continues to be on understanding the basic mechanisms underlying learning and developmental plasticity, an important goal of the next project period is to provide our students with new opportunities to discover how these principles can be used to stimulate the brain to repair and recover from damage and disease.

DESCRIPTION (provided by applicant): The purpose of the proposed research is to provide a comprehensive account of the factors that affect how infants, children, and adults learn the categories of their native language from distributional information in linguistic input. The categories of a language consist of sets of words (e.g., noun, verb) that play a functionally equivalent role in grammatical sentences. Distributional information refers to the patterning of elements in a large corpus of sentences and includes how frequently those elements occur, what position they occupy in a sentence, and the context provided by neighboring elements. Our longstanding program of research on statistical learning in word segmentation (how learners determine which sound sequences form words) has documented the power, rapidity, and robustness of infants, children, and adults sensitivity to complex distributional information. Here we extend that program of research to a crucial aspect of learning higher-level structures of language. In our proposed studies, we use a miniature artificial language paradigm that affords us complete control over all the distributional cues in the input, something that is virtually impossible using real languages. Participants listen to a sample of utterances and make judgments about their acceptability. Crucially, during a learning phase, they do not hear all possible utterances that are legal in the artificial language; some are withheld for use in a later post-test. The post-test utterances either conform to the distributional patterns present in the learning phase, or they violate those patterns. The key test is whether participants judge novel-but-legal utterances to be acceptable, thereby showing the ability to generalize correctly beyond the input to which they were exposed. Studies of children provide additional support for learning the distributional cues by pairing utterances with videos of simple events. Studies of adults will be used for comparison, and will also present them with learning materials in the visual-motor domain to assess the detailed time-course of learning and the specificity of the results to auditory linguistic materials. Taken together, the results of these studies of infants, children, and adults will document the key structural variables in language learning that enable a distributional mechanism of category formation to operate and will highlight the ways these mechanisms may differ over age and domain. PUBLIC HEALTH RELEVANCE: Language development is one of the hallmarks of the human species, yet it is difficult to study because of the huge variation in early exposure to different amounts of linguistic input. The use of artificial languages that are acquired in the lab over a few hours provides a window on the mechanisms of language development. We will study language learning in the lab to gain a unique perspective on how the categories (noun, verb, etc) are formed from listening to the patterns of words in a small set of sentences. These studies will not only reveal a basic mechanism of language learning, but also establish benchmarks against which language delay can be compared. Moreover, understanding the mechanisms that lead to successful acquisition in normal children can help to identify loci of language disorders and design methods for remediating disorders.

? DESCRIPTION (provided by applicant): For 35 years I have worked on language acquisition, conducting behavioral studies of children learning their first languages and the mechanisms of learning that make children so skilled in language acquisition. I've recently become interested in the related question of developmental plasticity in recovery from brain injury. I spent 2011-12 as a visitor to Georgetown University Medical Center (GUMC) and the National Rehabilitation Hospital (NRH), where I observed adult and child stroke patients and fMRI studies of language reorganization in epilepsy. I found this work completely gripping and am now refocusing my research on stroke recovery in children. In July 2012 I accepted a faculty position at Georgetown University as Director of a Center for Brain Plasticity and Recovery and have been starting to do research on pediatric stroke recovery. I am applying for a K18 award to provide myself with time over the next 2 years to enhance my research skills in studying the organization of language after childhood stroke, through a comprehensive and well- structured training and research plan under the direction of the outstanding mentors and consultants available to me at GUMC, NRH, and CNMC. I have already done extensive clinical observation. My training plan includes coursework, individual meetings, directed readings, and research training on using neuropsychological, fMRI, and DTI techniques to understand neural mechanisms of reorganization of language in children after perinatal stroke. My mentors will be Dr. Alexander Dromerick (adult stroke recovery, patient recruiting and research) and Dr. William Gaillard (fMRI research on child language reorganization after brain injury), with a team that will train me on adult aphasia and recovery (Dr. Peter Turkeltaub), pediatric stroke (Dr. Jessica Carpenter), functional imaging (Dr. John VanMeter), neuropsychological assessment (Dr. Madison Berl), and advanced techniques in analysis of patient and stroke imaging (Dr. Peter Turkeltaub) and in connectivity analyses (Dr. Chandan Vaidya). I will attend a course on fMRI and an advanced fMRI workshop and attend a semester-long course at GUMC providing advanced training in responsible conduct in research. I will also conduct a research study on language in children who have had a left hemisphere perinatal stroke. This project will focus on older children, many years after stroke, using fMRI, DTI, and behavioral techniques to examine the patterns and principles of how language is organized in the brain after stroke. The ultimate aim of this work is to improve stroke recovery in children and adults by understanding successful language organization in children. While this long-term goal is beyond the scope of the present proposal, the proposed training will be crucial in allowing me to proceed on to independent research in this new field.

PROJECT SUMMARY It has long been argued that the brain is most plastic during early development and that after brain injury, children reorganize cortical functions to healthy areas; but there is little understanding of these processes. Many investigators have shown that, when the left hemisphere (LH) is damaged, language can be subserved by the right hemisphere (RH). Here we ask how the linguistic functions of LH and RH are organized after LH injury and how well this atypical organization supports linguistic abilities. We also investigate the complementary questions regarding how these functions are organized after RH injury. We will study the long-term outcomes after ischemic perinatal stroke (IPS), due to its relatively clean properties for scientific analysis. IPS occurs in 1/4000 births and is the leading known cause of cerebral palsy. Many children with LH perinatal stroke develop near-normal language and cognitive abilities, but a substantial number show later language and cognitive impairments. Most literature shows that, after early LH stroke, language `reorganizes' to homotopic RH areas. Our pilot data suggest that, under these circumstances, typical LH and RH language functions divide up the RH cortical territory in new ways. We hypothesize that these functions develop best when different language functions find distinct RH localizations; overlap of linguistic functions will lead to more impaired performance. We will test this hypothesis by investigating language after LH perinatal injuries. We will also ask the same questions after RH perinatal injuries. We will recruit 30 teenagers and young adults who have had a LH perinatal stroke involving the middle cerebral artery and 30 who have had a similar RH perinatal stroke, compared with 30 healthy controls matched in age and SES. While IPS is rare, our research team is ideal for successful recruiting. We have developed our tasks and tested 16 children with perinatal strokes. We will administer a battery of behavioral and neuropsychological tests and 5 fMRI tasks. Two fMRI tasks (examining naming and sentence processing) test language functions that activate LH language areas in healthy controls. Two fMRI tasks (examining vocal emotion and intonation) test functions ordinarily controlled by the RH. Together these tasks examine how language abilities are affected when they develop in one hemisphere. An additional fMRI task examines specific object recognition (word recognition, ordinarily in LH VWFA, and face recognition, ordinarily in RH FFA) to ask if these functions are altered when their typical neural substrates are intact but language is shifted. Our behavioral tests assess how well all of these skills operate when neural organization is atypical. These studies will contribute to our understanding of the flexibility and limitations of early brain plasticity. In the future our findings can also help to provide a foundation for developing techniques to stimulate the most successful types of functional organization after early brain injuries.